WO2025233935A1

WO2025233935A1 - Cutting tool abutment surface

Info

Publication number: WO2025233935A1
Application number: PCT/IL2025/050375
Authority: WO
Inventors: Chen BALBES; Minerva RUILOBA
Original assignee: Iscar Ltd
Current assignee: Iscar Ltd
Priority date: 2024-05-06
Filing date: 2025-05-04
Publication date: 2025-11-13
Anticipated expiration: 2026-11-06

Abstract

A cutting tool includes an abutment surface and a support portion supporting the abutment surface. The abutment surface includes a first abutment sub-surface and a second abutment sub surface adjacent to the first abutment sub-surface. The support portion including a first support sub portion supporting the first abutment sub-surface, and a second support sub-portion supporting the second abutment sub-surface. The first and second support sub-portions have different constructions resulting in the first and second abutment sub-surfaces having a different stiffness values.

Description

CUTTING TOOL ABUTMENT SURFACE

FIELD OF THE INVENTION

[001] The subject matter of the present application relates to a cutting tool abutment surface (also called herein an "abutment surface" for conciseness). The abutment surface is configured to be abutted by another element.

BACKGROUND OF THE INVENTION

[002] Most cutting tools for metal workpieces use cemented carbide cutting inserts (also called "inserts" hereinafter) for a variety of reasons. However, for some machining applications a ceramic cutting insert, which is more brittle than cemented carbide, is preferred.

[003] Due to production difficulties, ceramic cutting inserts have a comparatively basic shape, for example with a single projecting prismatic lower surface (or V-shaped lower surface) and a flat rake surface opposite thereto. By contrast, a cemented carbide insert for a similar application would typically have an internal prismatic lower surface (i.e. a recessed V-shape) and a rake surface with a chip forming construction.

[004] During the development of a cutting tool for a ceramic cutting insert a new abutment surface for an insert pocket was developed to mitigate the possibility of the comparatively more brittle ceramic cutting insert from breaking.

[005] The new abutment surfaces are able to be produced both with additive and subtractive production methods as will be exemplified below.

[006] Subsequently, it was understood that the new development may be of benefit for insert pockets which are not designed for ceramic cutting inserts and may also be of benefit for cutting tools with abutment of two parts, even when the abutment surface is not an insert pocket abutment surface. [007] It is an object of the present invention to provide an improved cutting tool, and more precisely an improved cutting tool abutment surface.

SUMMARY OF THE INVENTION

[008] In accordance with a first aspect of the subject matter of the present application, there is provided a cutting tool comprising: an abutment surface; and a support portion supporting the abutment surface; the support portion comprising a first stiffness value KI at a first abutment sub- surface and a second stiffness value K2 at a second abutment sub-surface; wherein the first stiffness value KI fulfills the condition: KI > K2.

[009] In accordance with a second aspect of the subject matter of the present application, there is provided a cutting tool comprising: an abutment surface; and a support portion supporting the abutment surface; the abutment surface comprising: a first abutment sub-surface; a second abutment sub-surface adjacent to the first abutment sub-surface; the support portion comprising: a first support sub-portion supporting the first abutment sub-surface and having a first material-void construction providing the first abutment sub-surface with a first stiffness value KI; a second support sub-portion supporting the second abutment sub-surface and having a second material-void construction providing the second abutment sub-surface with a second stiffness value K2; wherein the first stiffness value KI fulfills the condition: KI > K2.

[0010] It was found that by having different stiffness values along a single abutment surface, a beneficial abutment arrangement is achievable.

[0011] To elaborate, a first example will be given.

[0012] One type of known insert pocket (not shown) for elongated double-ended grooving inserts has a base surface (which will be the abutment surface comparison) which is recessed in the middle thereof, to ensure that only an extremity sub-surfaces of the elongated insert abuts the abutment surface to ensure optimum stability. An alternative design is for such recess to be in the insert itself (not shown). However, such known designs are for cemented carbide inserts and it has been found by the present inventors that they are more likely to result in breakage of ceramic inserts which are more brittle (i.e. more likely to break under bending forces).

[0013] It was then conceived to provide a continuous support abutment surface on both on the cutting insert's abutment surface and the pocket's base surface (i.e. abutment surface) and to design the area supporting the abutment surface (i.e. the support portion) to distribute the abutment forces so that the desired extremities would be more rigid and in the center of the abutment surface there would be significantly more displacement reducing instability. To explain, if a continuous (i.e. extending in a straight line) insert abutment surface and corresponding pocket base surface is provided without a modified support portion, there would likely be more force in the center of the base surface, rather than extremity areas, and the mounting of the cutting insert would likely be less stable (noting that cutting inserts are extremely rigid and products manufactured are only produced within tolerances). Accordingly, good stability is maintained without a recess formed on either the insert or the pocket abutment surface, which could cause breakage of a ceramic insert. It will be understood that while this concept was conceived for ceramic inserts, the application thereof may be beneficial even for other materials (e.g. more common inserts such as those made of cemented carbide).

[0014] In other words, the abutment surface is configured to have a first sub-surface configured for more displacement than a second sub-surface adjacent to the first sub-surface. For some preferred embodiments the abutment surface is configured for the most displacement at the center thereof. For some preferred embodiments the abutment surface is configured to follow a pattern from a first extremity to a second extremity, of increasing and then decreasing displacement.

[0015] Notably, unlike the first example given above, the first aspect is not restricted to two extremity sub-surfaces with variable stiffness sub-surfaces therebetween, but rather only two subsurfaces with different stiffnesses. An example will be given below (i.e. second side abutment surface 218) where it is beneficial for an abutment surface to have only one extremity with higher stiffness than a second extremity (i.e. without a higher-lower-higher stiffness pattern, or increasing and then decreasing displacement pattern, described above in connection with the first example). Stated differently, the abutment surface is only intended to provide abutment at one side thereof, namely, a side surface of an insert pocket may have only one intended abutment sub-surface, yet production of the insert pocket may be more simple (particularly in the case of 3D printed tools) to have a continuous abutment sub-surface. Again, the invention provides more stability to a cutting insert where the most spaced apart sub-surfaces bear the most abutment forces for better stability.

[0016] While the above-described examples are primarily directed to abutment surfaces designed to be abutted by cutting inserts (i.e. insert pocket abutment surfaces), it should be understood that other regions where two components of a cutting tool abut may benefit from the present invention. For example, an abutment surface adjacent a screw hole is exemplified below. While the particular screw hole exemplified is part of an insert pocket, the same beneficial effect may be brought for a screw hole for securing two components of a cutting tool not including a cutting insert.

[0017] An embodiment of which is described below in connection with Figures 9 and 10, which show an abutment surface and support portion according to the present invention is formed on a cutting tool holder configured to secure a cutting tool (which in this non-limiting example is a partingblade) rather than an abutment surface is configured to abut a cutting insert. It will be understood that the abutment surface and support portion according to the invention could additionally or alternatively be on the cutting tool. For example, referring to Fig. 9A, the cutting tool (i.e. the parting blade) could be formed with at least one abutment surface and support portion (not shown). Such cutting tool could also be used with a standard cutting tool holder (not shown). In such case the standard cutting tool holder could preferably have a top clamp which is devoid of elasticity slits (which are common for such cutting tool holders).

[0018] It will be understood that an abutment surface can also be perforated, such as with a screw hole or, for example, simply to be the uppermost surface of a lattice. While it is preferred for the abutment surface to be a solid layer (or enclosure) because such surfaces are typically post machined to high precision, it is feasible that such abutment surfaces may not be post machined with ever improving additive printers increasingly showing higher precision.

[0019] While all embodiments shown below can be produced with 3D printing manufacturing processes (i.e. "additive manufacturing"), it will be understood that the desired invention could also be produced in a tool made with traditional subtractive manufacturing processes. For example, the embodiment shown in Fig. 1A can be produced by a traditional subtractive process, for example by laser cutting.

[0020] Stiffness values can be calculated with the standard equation: K = F / D (where K is stiffness, F is a force applied on an abutment sub-surface and D is a resulting displacement).

[0021] Preferably, from the first abutment sub-surface with increasing proximity towards the second abutment sub-surface, the abutment surface has a pattern of decreasing stiffness values. It will be understood that while certain points or sub-surfaces are selected for definition purposes, the invention results in a plurality or pattern of different values.

[0022] In such preferred embodiments, the abutment surface further comprises a third abutment subsurface adjacent to the second abutment sub-surface at an opposing thereof than the first abutment sub-surface, and the support portion further comprises a third support sub-portion supporting the third abutment sub-surface and having a third material-void construction providing the third abutment subsurface with a third stiffness value K3, wherein K3 > K2.

[0023] In such preferred embodiments, the second abutment sub-surface has a lower stiffness value than both the first and third abutment sub-surfaces on different sides thereof. This means that when an object such as a cutting insert is biased against all three sub-surfaces the second abutment subsurface is displaced more than the other sub-surfaces. This is particularly suiting for, but not limited to, abutment surfaces such as the pocket base surface example mentioned above.

[0024] Preferably, from the second abutment sub-surface with increasing proximity towards the third abutment sub-surface, the abutment surface has a pattern of increasing stiffness values.

[0025] It will be understood that while it is theoretically possible that a prior art tool may be found with an abutment surface with some sort of geometric design that coincidentally creates a small differential stiffness, the present invention is designed purposefully to provide a specific function. This may be realized by providing structures that are sufficiently close (depth-wise) to the abutment surface to affect stiffness. Accordingly, there are significant differences in stiffness to achieve the desired function. To quantify some preferable differences, preferably 0.8K3 > KI > 1.2K3, more preferably 0.85K3 > KI > 1.15K3 and most preferably 0.9K3 > KI > 1.1K3. Preferably, K2 < 0.75K1, preferably K2 < 0.5K1 and more preferably K2 < 0.35K1. Preferably, K2 < 0.75K3, preferably K2 < 0.5K3 and more preferably K2 < 0.35K3.

[0026] In some preferred embodiments, the tool comprises a clamp configured to apply force in a direction towards the abutment surface. The clamp can be of any suitable type, for example a screw, lever or an integral tool clamp.

[0027] Preferably, the abutment surface is part of an insert pocket or tool pocket. Regardless, the component comprising the abutment surface (also referred to hereinafter "first abutment surface") and associated support portion can comprise one or more additional abutment surfaces (each of which having an associated support portion) according to the present invention. The one or more additional abutment surfaces are spaced apart from the first abutment surface. Preferably, one or more of the additional abutment surfaces can in the same orientation as the first abutment surface. Preferably, one or more of the additional abutment surfaces can be oriented orthogonally to the first abutment surface. [0028] According to some preferred embodiments, the first material-void construction is a first lattice structure and the second material- void construction is a second lattice structure having a larger void-to-material percentage than the first lattice structure.

[0029] A larger void-to-material percentage means that in a given region of the tool the void percentage is greater than the material percentage. Consequently, when a force is applied against that region there is more displacement (because there is lower stiffness) than an area where there is a greater percentage of material.

[0030] According to some preferred embodiments, the abutment surface further comprises a first extremity sub-surface located at a first end of the abutment surface and adjacent to the first abutment sub-surface, and the support portion comprises a first extremity support sub-portion supporting the first extremity abutment sub-surface and having a first extremity material-void construction providing the first extremity abutment sub-surface with a first extremity stiffness value KE1, wherein KE1 > KI. Preferably, the first extremity material-void construction has a solid construction. It will be understood that typically a first extremity sub-surface is preferred, however it is possible for the desired abutment to occur even with most forces being on a abutment sub-surface which has a support sub-portion which is not a solid construction.

[0031] A solid construction is considered to be devoid of voids.

[0032] According to some preferred embodiments, there is a third support sub-portion, wherein the third material-void construction is a third lattice structure having a smaller void to material percentage than the second lattice structure.

[0033] According to some preferred embodiments, the abutment surface further comprises a second extremity sub-surface located at a second end of the abutment surface distal to the first end, and the support portion comprises a second extremity support sub-portion supporting the second extremity abutment sub-surface and having a second extremity material-void construction providing the second extremity abutment sub-surface with a second extremity stiffness value KE2, wherein KE2 > KI. Preferably, the second extremity material-void construction has a solid construction.

[0034] According to some preferred embodiments, the first material-void construction is a solid construction extending a first distance DI from the first abutment sub-surface to a first void, and the second material-void construction is a solid construction extending a second distance D2 from the second abutment sub-surface to a second void; the first distance fulfilling the condition: DI > D2 [0035] Preferably, the first void and the second void are sub-portions of a single void. It will be understood that this can allow for ease of manufacture.

[0036] Preferably, the cutting tool further comprises a third abutment sub-surface and the third material-void construction, wherein the third material-void construction is a solid construction extending a third distance D3 from the first abutment sub-surface to a third void; the third distance fulfilling the condition: D3 > D2. Preferably, the first void, the second void and the third void are subportions of a single void.

[0037] Preferably, the single void has an elongated shape. More preferably, the single void has an arc-shape. Preferably, the apex of the arc shape is closest to the second abutment sub-surface. Preferably, the arc shape is mirror symmetrical about the second void.

[0038] According to some preferred embodiments, the abutment surface further comprises a first extremity sub-surface located at a first end of the abutment surface and adjacent to the first abutment sub-surface, and the support portion comprises a first extremity support sub-portion supporting the first extremity abutment sub-surface and having a first extremity material-void construction providing the first extremity abutment sub-surface with a first extremity stiffness value KE1, wherein KE1 > KI. Preferably, the first extremity material-void construction has a solid construction. [0039] According to some preferred embodiments, the abutment surface further comprises a second extremity sub-surface located at a second end of the abutment surface distal to the first end, and the support portion comprises a second extremity support sub-portion supporting the second extremity abutment sub-surface and having a second extremity material-void construction providing the second extremity abutment sub-surface with a second extremity stiffness value KE2, wherein KE2 > KI. Preferably, the second extremity material-void construction has a solid construction.

[0040] Preferably, at least one material-void construction opens out to at least a first side surface of the cutting tool. More preferably, the material-void construction also opens out to a second side surface of the cutting tool. It will be understood that while the material-void constructions can be enclosed within solid surfaces, it is preferred that they are visible as shown in most of the embodiments, since an outer solid surface can increase their stiffness and lessen the desired displacement (where such is desired). Nonetheless, in certain circumstances such as a concern that chips or machined particles might enter the material-void construction, or if the construction is not stiff enough and a solid wall would add to a desired structural strength, it is feasible that the materialvoid construction could be closed on one or both sides.

[0041] Preferably, the abutment surface extends linearly (i.e. along a straight line from a side view) from a first extremity sub-surface to a second extremity sub-surface.

[0042] Preferably, the abutment surface; and the support portion are made from a homogenous material. Preferably, the homogenous material is steel. Stated differently, the present invention provides select surfaces with variable qualities, through a material-void construction to be described below (rather than through using different material types).

[0043] Preferably, the cutting tool further comprises a ceramic cutting insert mounted on the abutment surface wherein a base insert surface of the of the cutting insert corresponds in shape to the abutment surface. Most preferably, both being linear (i.e. planar) surfaces, or having planar surfaces. [0044] In some preferred embodiments, the abutment surface has an abutment surface length LA; the first void and the second void are sub-portions of an arc-shaped single void; the single void has a void length Lv measured in a direction parallel to the abutment surface.

[0045] Preferably, the void length Lv is smaller than the abutment surface length LA.

[0046] Preferably, the void length Lv is greater than the distances DI and D2.

[0047] Preferably, the cutting tool further comprises a third abutment sub-surface and a third material-void construction, wherein the third material-void construction is a solid construction extending a third distance D3 from the first abutment sub-surface to a third void, the third distance fulfilling the condition D3 > D2; and the void length Lv is greater than the distances DI, D2 and D3. [0048] An abutment surface can have an abutment surface width WA. A material-void construction can have a material-void construction width WV. In some preferred embodiments the material void construction width fulfills the condition: WV > WA. This can provide additional displacement (or stated differently reduced stiffness), even though a portion of the material-void construction is not directly adjacent (in a direction perpendicular to the abutment surface) to the abutment surface. This feature can be useful when there are space restrictions in a direction perpendicular to the abutment surface.

[0049] In some preferred embodiments the material-void construction comprises a void proximal surface closest to the abutment surface, and the void proximal surface extends in the same basic direction as the abutment surface. It will be understood that a desired stiffness characteristic does not require the void proximal surface to extend in an exact parallel direction. Nonetheless, in some preferred embodiments the void proximal surface is parallel with the abutment surface.

[0050] In some preferred embodiments, in a direction orthogonal to the direction from the first abutment sub-surface to the second abutment sub-surface, the material-void construction can be curved or comprise a bend. This feature can be useful when there are space restrictions in a direction perpendicular to the abutment surface.

[0051] In accordance with another aspect of the subject matter of the present application, there is provided a cutting tool comprising: an abutment surface comprising: a first abutment sub-surface; and a second abutment sub-surface adjacent to the first abutment sub-surface; and a support portion underlying the abutment surface, and comprising: a first support sub-portion supporting the first abutment sub-surface and providing the first abutment sub-surface with a first stiffness value KI, the first support sub-portion comprising a solid construction extending a first distance D 1 from the first abutment sub-surface to a first void; and a second support sub-portion supporting the second abutment sub-surface and providing the second abutment sub-surface with a second stiffness value KI, the second support sub-portion comprising a solid construction extending a second distance D2 from the second abutment sub-surface to a second void; wherein: the first stiffness value KI fulfills the condition KI > K2; the first distance DI fulfills the condition DI > D2; the abutment surface has an abutment surface length (LA); the first void and the second void are sub-portions of an arc-shaped single void; the arc-shaped single void has a void length (Lv) measured in a direction parallel to the abutment surface; the void length (Lv) is smaller than the abutment surface length (LA); and the void length (Lv) is greater than the distances D 1 and D2.

[0052] The cutting tool preferably further comprising: a third abutment sub-surface adjacent to the first abutment sub-surface on an opposite side from the second abutment sub-surface; and a third support sub-portion supporting the third abutment sub-surface and providing the third abutment subsurface with a third stiffness value K3, the third support sub-portion comprising a solid construction extending a third distance D3 from the first abutment sub-surface to a third void; wherein: the third stiffness value K3 fulfills the condition K3 > K2; the third distance D3 fulfills the condition D3 > D2; the first void, the second void and the third void are all sub-portions of the arc-shaped single void; and the void length (Lv) is greater than the distances DI, D2 and D3.

BRIEF DESCRIPTION OF THE DRAWINGS

[0053] For a better understanding of the subject matter of the present application, and to show how the same may be carried out in practice, reference will now be made to the accompanying drawings, in which:

Fig. 1 A is a perspective view of a cutting tool and a cutting insert mounted thereto;

Fig. IB is another perspective view of the cutting tool and cutting insert in Fig. 1A;

Fig. 1C is a side view of the cutting tool and the cutting insert in Fig. 1A;

Fig. 2A is a perspective view of the cutting insert in Fig. 1A;

Fig. 2B is another perspective view of the cutting insert in Fig. 2A;

Fig. 2C is a first side view of the cutting insert in Fig. 2A;

Fig. 2D is a front view of the cutting insert in Fig. 2A;

Fig. 2E is a top view of the cutting insert in Fig. 2A;

Fig. 2F is a rear view of the cutting insert in Fig. 2A;

Fig. 2G is a second side view of the cutting insert in Fig. 2A;

Fig. 3A is a top view of the cutting tool in Fig. 1A;

Fig. 3B is a front view of the cutting tool in Fig. 3A;

Fig. 3C is a side view of the cutting tool in Fig. 3A;

Fig. 3D is a rear view of the cutting tool in Fig. 3A;

Fig. 3E is a bottom view of the cutting tool in Fig. 3A;

Fig. 4 is an enlarged view of the area encircled in Fig. 3C;

Fig. 5 is another embodiment, and is shown in a view corresponding to Fig. 3C; Fig. 6 A is a perspective view of the support portion in Fig. 5;

Fig. 6B is a top view of the support portion in Fig. 6A;

Fig. 6C is a side view of the support portion in Fig. 6A, and is an enlarged view of the support portion shown in Fig. 5;

Fig. 6D is an end view of the support portion in Fig. 6A;

Fig. 7 is a different embodiment of a cutting tool, and is shown in perspective view;

Fig. 8A is a perspective view of three support portions of the insert pocket shown in Fig. 7, oriented in the same orientation as they are in Fig. 7 (although not seen in Fig. 7 because they are hidden by respective abutment surfaces) and enlarged;

Fig. 8B is a top view of the three support portions in Fig. 8A;

Fig. 9A is a perspective view of a cutting tool assembly;

Fig. 9B is a side view of the cutting tool assembly in Fig. 9A;

Fig. 10A is a perspective view of a cutting tool holder clamp (hereinafter "clamp") of the cutting assembly in Fig. 9A;

Fig. 10B is a front view of the clamp in Fig. 10A;

Fig. 10C is a perspective view of the clamp in Fig. 10A with internal components shown in dashed lines; and

Fig. 10D is a front view perspective view of the clamp in Fig. 10A with internal components shown in dashed lines.

DETAILED DESCRIPTION

[0054] Reference is made to Figs. 1A to 1C and 3C, which illustrate a cutting tool 10 made of steel and a cutting insert 12 made of ceramic. The cutting tool 10 comprises a resilient insert pocket 14 in turn comprising a base surface 16 and, oppositely located to the base surface, a clamp 18 comprising a clamp surface 20.

[0055] The cutting insert 12 is mounted to the cutting tool 10 and is held between the base surface 16 and the clamp surface 20.

[0056] Referring to Figs. 2A to 2G, the cutting insert 12 comprises an insert front end 22 and an insert rear end 24 opposite thereto, a planar- shaped rake surface 26 and a V-shaped insert bottom surface 28 opposite thereto and insert first and second side surfaces 30, 32.

[0057] The insert rear end has a stopper 34. [0058] The insert front end 22 and insert side surfaces 30, 32 are all slightly inclined inwardly from the rake surface 26 and in a direction away from the rake surface 26, to provide clearance during machining.

[0059] Referring to Figs. 3 A to 3E, the cutting tool 10 comprises a tool front end 36 and a tool rear end 38 opposite thereto, a tool upper surface 40 and a tool lower surface 42 opposite thereto, and tool first and second side surfaces 44, 46.

[0060] Referring to Fig. 4, the base surface 16 (which will be hereinafter called the "abutment surface 16" to assist understanding of the claims) and a support portion 48 supporting the abutment surface will be described in detail. Generally speaking, the support portion 48 underlies the abutment surface 16.

[0061] The abutment surface 16 comprises a first end 50 and distally located second end 52, a first extremity sub-surface 16A having a first extremity stiffness value KE1, a first abutment sub-surface 16B having a first stiffness value KI, a second abutment sub-surface 16C having a second stiffness value K2, a third abutment sub-surface 16D having a third stiffness value K3, and a second extremity sub-surface 16E having a second extremity stiffness value KE2.

[0062] The support portion 48 comprises a first extremity support sub-portion 48A, a first support sub-portion 48B, a second support sub-portion 48C, a third support sub-portion 48D and a second extremity support sub-portion 48E.

[0063] The first extremity support sub-portion 48 A has a material- void construction which is a solid construction, i.e. which is devoid of voids adjacent to the first extremity sub-surface 16A.

[0064] The first support sub-portion 48B has a material-void construction having a solid construction extending a first distance DI (the distances being taken at the center of the respective sub-portion) from the first abutment sub-surface 16B to a first void 54B (the first void 54B could alternatively be called a first void portion, since in this example there is only a single void; this comment also applies mutatis mutandis for the voids mentioned below in connection with this embodiment). Given the curving nature of the voids in this embodiment, the distances could alternatively be called "average" distances. It should be noted that the reference character 54A has deliberately been omitted for ease of reading, i.e. consistent use of suffixed letters for related elements. [0065] As the first support sub-portion 48B has a first void (or first void portion) adjacent to the first abutment sub-surface 16B, whereas no such void is similarly located adjacent to the first extremity sub-surface 16A, the first stiffness value KI at the first abutment sub-surface 16B is lower than the first extremity stiffness value KE1 at the first extremity sub-surface 16 A. [0066] The second support sub-portion 48C has a material-void construction having a solid construction extending a second distance D2 from the second abutment sub-surface 16C to a second void 54C.

[0067] As the second support sub-portion 48C has a second void 54C adjacent to the second abutment sub-surface 16C, at a second distance D2 which is smaller than the first distance DI, and as a result of the smaller distance, the second stiffness value K2 at the second abutment sub-surface 16C is lower than the first stiffness value KI at the first abutment sub-surface 16B.

[0068] The third support sub-portion 48D has a material-void construction having a solid construction extending a third distance D3 from the third abutment sub-surface 16D to a third void 54D.

[0069] As the third support sub-portion 48D has a third void 54D adjacent to the third abutment subsurface 16D, at a second distance D3 which is larger than the second distance D2, and as a result of the larger distance, the third stiffness value K3 at the third abutment sub-surface 16D is higher than the first stiffness value K2 at the second abutment sub-surface 16C.

[0070] In this example, the first distance DI and the third distance D3 are equal and therefore so are the first stiffness value KI and the third stiffness value K3.

[0071 ] The second extremity support sub-portion 44E has a material-void construction which is a solid construction, similar to the first extremity support sub-portion 48A. Consequently, the first extremity stiffness value KE1 and the second extremity stiffness value KE2 are also equal.

[0072] As shown, in this example, the first, second and third voids are sub-portions of a single void having an elongated mirror symmetrical arc shape with an apex 55 (Fig. 1C) closest to the second abutment sub-surface.

[0073] As the single void 54 is arc-shaped (i.e. with a gradually increasing or decreasing distance thereto from the abutment surface) intermediary points along the abutment surface will have different stiffness values. For example, between the first stiffness value KI and the second stiffness value K2, there can be measured a fourth stiffness value K4, which would fulfill the condition: KI > K4 > K2. Thus there is a pattern of decreasing stiffness from the first abutment sub-surface 16B to the second abutment sub-surface 16C.

[0074] Similarly, for example, between the second stiffness value K2 and the third stiffness value K3, there can be measured a fifth stiffness value K5, which would fulfill the condition: K2 < K5 < K3. Thus there is a pattern of increasing stiffness from the second abutment sub-surface 16C to the third abutment sub-surface 16D. [0075] The abutment surface 16 has an abutment surface length LA measured in the principal direction of the abutment surface 16. The single void 54 has a void length Lv measured in a direction parallel to the direction along which the abutment surface length LA is measured. The void length Lv is smaller than the abutment surface length LA and may satisfy the condition 0.5 LA < Lv < 0.8 LA. [0076] Furthermore, to realize meaningful differences in stiffness values KI, K2 and K3 at the first, second and third voids 54B, 54C, 54D, the void length Lv is greater than all of the DI, D2, D3, i.e., Lv > max (DI, D2, D3). Restated, the void length Lv is greater than the maximum distance from the void 54 to the abutment surface 16.

[0077] The single void 54 opens out to both the tool first side surface 44 and the tool second side surface 66. While the tool 10 exemplified was designed to be produced with additive manufacturing, the single void 54 could also be produced, for example by laser or other subtractive manufacturing methods.

[0078] Referring now to Figs. 5 to 6D, another cutting tool 100 is shown, with identical elements being designated with the same reference numerals.

[0079] The only significant difference is that the different stiffness values at the abutment surface 16 are provided with a lattice structure 56 rather than the void 54 shown in the previous embodiment. [0080] The lattice structure 56 is additively printed, together with the entire tool 100. However, it is also conceivable that such structure could be produced separately and connected to a tool in the position shown.

[0081] In this lattice structure embodiment, rather than having a solid construction for a given distance from the abutment surface to a void, there is a plurality of voids which produce the desired effect by either being more numerous and/or differing in size, within a given region. Changing either the numerosity or the size of the voids can change “void percentage” in a given region, thereby affecting the stiffness in that region.

[0082] Even though the principles are the same as previously described, for the sake of good order some details are elaborated.

[0083] A first support sub-portion 116B has a material- void construction which is a first lattice structure. It will be understood that in the previous embodiment the material-void constructions were solid constructions which in some cases had a void at a specific distance, whereas here there are a plurality of voids (and even the plurality differ in size). Yet no separate reference numeral is provided for a "lattice structure" which is just a simplified description of the type of material-void construction. [0084] A second support sub-portion 116C has a material-void construction which is a second lattice structure.

[0085] A third support sub-portion 116D has a material-void construction which is a third lattice structure.

[0086] As shown, the second support sub-portion 116C, i.e. the second lattice structure thereof, has a larger void-to-material percentage than the first and third lattice structures 116B, 116D.

[0087] Referring now to Figs. 7 to 8D, yet another tool 200 is shown. The same invention is shown here applied to a different type of insert pocket 214 which is not of the resilient type but is configured for a clamp in the form of a screw (not shown).

[0088] The insert pocket 214 comprises a first side abutment surface 216, a second side abutment surface 218 and a base abutment surface 220 formed with a screw hole 222.

[0089] Figs. 8A and 8B show the internal construction behind each of the abutment surfaces (216, 218, 220) which is covered by a continuous surface.

[0090] Behind the first side abutment surface 216 is a first lattice structure 224. The first lattice structure 224 functions in a similar manner to the previously described embodiments, with material reduced in the center 225 thereof to achieve a lower stiffness at the center 225 and better abutment at the extremities thereof 227.

[0091] Behind the second side abutment surface 218 is a second lattice structure 226. The second lattice structure 226 is an example of where there is only one intended abutment end 228 as opposed to all of the previous examples. In this example, a distal end 230 of the second lattice structure 226 has a larger void-to-material percentage than the intended abutment end 228. Thus, the distal end 230 provides support to a cutting insert (not shown), but allows stability as described above and avoids breakage of the cutting insert. Further, such design may allow easier production via additive manufacturing as no recessed area is needed, allowing ease of production in more printing directions. [0092] The base abutment surface 220 comprises a third lattice structure 232, which has a larger void-to-material percentage at an area 234 encircling the screw hole 222, relative to the extremities 236 of the remainder of the third lattice structure 232.

[0093] Referring now to Figs. 9A and 9B, a different embodiment, which in this case is a cutting tool assembly 300, is shown.

[0094] The cutting tool assembly 300 comprises a cutting tool 310 which is made of steel and which has a cutting insert 312 made of cemented carbide mounted thereto. The cutting tool assembly 300 further comprises a cutting tool holder 314 which in turn comprises a cutting tool holder body 316, a cutting tool holder clamp 318 (or "clamp), and a plurality of screws 320 holding the clamp 318 to the cutting tool holder body 316 and which also assist in securing the cutting tool 310 to the cutting tool holder 314.

[0095] Except for the clamp 318, the remainder of the components of the cutting tool assembly 300 are standard components and will not be detailed further.

[0096] Referring also to Figs. 10A to 10D, the clamp 318 will be described in further detail. Notably, only non-standard elements or elements facilitating understanding of the invention will be described. [0097] The clamp 318 comprises a front end 322, a rear end 324 opposite to the front end 322, a first side surface 326, a second side surface 328 opposite to the first side surface 326, a top surface 330, a bottom surface 332 opposite to the top surface 330, and a plurality of screw holes 334 extending from, and opening out to, the top surface 330 and the bottom surface 332.

[0098] The bottom surface 332 comprises an abutment surface 336 which is slanted relative to the adjacent first side surface 326 (i.e. forming an internal acute angle 0 therewith).

[0099] The above features are all common with known clamps of this type.

[00100] Often, traditional clamps are formed with an elasticity slit (not shown) extending between two adjacent screw holes 334 and opening out to the first side surface 326 and the abutment surface 336. This is advantageous for force distribution but causes high stress areas near the elasticity slit at the abutment surface 336 because a relatively sharp corner which clamps the cutting tool 310.

[00101] In the present embodiment there are no elasticity slits but rather the abutment surface 336 comprises a first abutment surface 338 and associated first support portion 340 (located between two adjacent screw holes 334), and a second abutment surface 342 and associated second support portion 344 (located between two adjacent screw holes 334).

[00102] This arrangement provides an advantageous variable stiffness as described above, without the disadvantage of the high stress areas. Additionally, in the known clamps with elasticity slits, when a parting blade is greatly protruded for additional cut depth, a portion of the clamp associated with an end screw may not contact the parting blade causing the clamp to be crooked, such effect being avoided by the shown embodiment of the invention. For the sake of good order, it is noted that this arrangement allows the entire abutment surface 336 to clamp the cutting tool 310 and not only the portions thereof (i.e. the first and second abutment surfaces 338, 342).

[00103] Notably, the first and second abutment surfaces 338, 342 and their associated first and second support portions 340, 344 are in the same orientation, merely spaced apart. This is in contrast to the example in Fig. 7 which has first, second and third abutment surfaces (216, 218, 220) in basically, relative, orthogonal orientations.

[00104] Since each of the first and second abutment surfaces 338, 342 and their associated first and second support portions 340, 344 function similarly to the previous embodiments, only differences of note will now be discussed.

[00105] Additionally, the first and second support portions 340, 344 are identical and therefore only the first support portion 340 will be described in detail.

[00106] The first support portion 340 has a material-void construction comprising a single void 346. The single void 346 opens out to only to the first side surface 326. The single void 346 has a closed end 348 located further from the first side surface 326 than the entire abutment surface 336. Stated differently, the abutment surface has abutment surface width WA, and the material-void construction (or single void 346 in this case) has a material-void construction width WV, and the material-void construction width WV is greater than the abutment surface width WA. This provides a lower stiffness value than if the single void would only extend directly above the first abutment surface 338.

[00107] While the single void could have opened out to the second side surface 328, in this case it was deemed preferable to keep structural strength near the second side surface 328. It will be understood though that this is a feasible alternative design option. Yet another design option is to increase a height of the void, but it was decided for this component (bearing in mind the design thereof and also the screw holes 334) that increasing the width and not the height would be more appropriate. [00108] Additionally, the material-void construction, or more precisely the single void 346 thereof) comprises a void proximal surface 350 closest to, and parallel with, the first abutment surface 338.

[00109] In a direction orthogonal DO to the elongation direction DE (Fig. 9B) of the first abutment surface 338 the material- void construction comprises a bend 352.

Claims

CLAIMS What is claimed is:

1. A cutting tool comprising: an abutment surface comprising: a first abutment sub-surface; and a second abutment sub-surface adjacent to the first abutment sub-surface; and a support portion supporting the abutment surface, and comprising; a first support sub-portion supporting the first abutment sub-surface and having a first material-void construction providing the first abutment sub-surface with a first stiffness value KI; and a second support sub-portion supporting the second abutment sub-surface and having a second material-void construction providing the second abutment subsurface with a second stiffness value K2; wherein the first stiffness value KI fulfills the condition: KI > K2.

2. The cutting tool as claimed in claim 1, wherein: the abutment surface further comprises a third abutment sub-surface adjacent to the second abutment sub-surface at an opposing side thereof than the first abutment sub-surface, and the support portion further comprises a third support sub-portion supporting the third abutment sub-surface and having a third material-void construction providing the third abutment sub-surface with a third stiffness value K3, wherein K3 > K2.

3. The cutting tool as claimed in claim 2, fulfilling the condition: 0.8K3 > KI > 1.2K3.

4. The cutting tool as claimed in any one of claims 1 to 3, fulfilling the condition: K2 < 0.75K1.

5. The cutting tool as claimed in any one of claims 1 to 4, wherein the tool comprises: a clamp configured to apply force in a direction towards the abutment surface; and the abutment surface is part of an insert pocket.

6. The cutting tool as claimed in any one of claims 1 to 5, wherein the first material-void construction is a first lattice structure and the second material-void construction is a second lattice structure having a larger void-to-material percentage than the first lattice structure.

7. The cutting tool as claimed in claim 6, whereim the abutment surface further comprises a first extremity sub-surface located at a first end of the abutment surface and adjacent to the first abutment sub-surface, and the support portion comprises a first extremity support sub-portion supporting the first extremity abutment sub-surface and having a first extremity material-void construction providing the first extremity abutment sub-surface with a first extremity stiffness value KE1, wherein KE1 > KI.

8. The cutting tool as claimed in claim 7, wherein the first extremity material-void construction has a solid construction.

9. The cutting tool as claimed in claim 7, further including a third support sub-portion, wherein the third material-void construction is a third lattice structure having a smaller void to material percentage than the second lattice structure.

10. The cutting tool as claimed in any one of claims 1 to 9, whereim the first material-void construction is a solid construction extending a first distance D 1 from the first abutment sub-surface to a first void, and the second material-void construction is a solid construction extending a second distance D2 from the second abutment sub-surface to a second void; the first distance fulfilling the condition: DI > D2.

11. The cutting tool as claimed in claim 10, wherein the first void and the second void are subportions of a single void.

12. The cutting tool as claimed in claim 11, wherein the single void has an arc-shape and an apex of the arc shape is closest to the second abutment sub-surface.

13. The cutting tool as claimed in any one of claims 10 to 12, further comprising a third abutment sub-surface and a third material-void construction, wherein the third material-void construction is a solid construction extending a third distance D3 from the first abutment sub-surface to a third void; the third distance fulfilling the condition: D3 > D2.

14. The cutting tool as claimed in any one of claims 10 to 13, wherein: the abutment surface further comprises a first extremity sub-surface located at a first end of the abutment surface and adjacent to the first abutment sub-surface, and the support portion comprises a first extremity support sub-portion supporting the first extremity abutment sub-surface and having a first extremity material-void construction providing the first extremity abutment sub-surface with a first extremity stiffness value KE1, wherein KE1 > KI, and the first extremity material-void construction has a solid construction.

15. The cutting tool as claimed in claim 14, wherein; the abutment surface further comprises a second extremity sub-surface located at a second end of the abutment surface distal to the first end, and the support portion comprises a second extremity support sub-portion supporting the second extremity abutment sub-surface and having a second extremity material-void construction providing the second extremity abutment sub-surface with a second extremity stiffness value KE2, wherein KE2 > KI, and the second extremity material-void construction has a solid construction.

16. The cutting tool as claimed in any one of claims 1 to 15, wherein at least one material-void construction opens out to at least a first side surface of the cutting tool.

17. The cutting tool as claimed in any one of claims 1 to 16, wherein the abutment surface extends linearly from a first extremity sub-surface to a second extremity sub-surface.

18. The cutting tool as claimed in any one of claims 1 to 17, wherein the abutment surface and the support portion are made from a homogenous material.

19. The cutting tool as claimed in any one of claims 1 to 18, further comprising a ceramic cutting insert mounted on the abutment surface wherein a base insert surface of the cutting insert corresponds in shape to the abutment surface.

20. The cutting tool as claimed in any one of claims 1 to 19, wherein: the abutment surface has an abutment surface length (LA); the first void and the second void are sub-portions of an arc-shaped single void; the single void has a void length (Lv) measured in a direction parallel to the abutment surface; the void length (Lv) is smaller than the abutment surface length (LA); and the void length (Lv) is greater than the distances D 1 and D2.

21. The cutting tool as claimed in claim 20, further comprising: a third abutment sub-surface and a third material-void construction, wherein the third materialvoid construction is a solid construction extending a third distance D3 from the first abutment subsurface to a third void, the third distance fulfilling the condition D3 > D2; and the void length (Lv) is greater than the distances DI, D2 and D3.